Unresponsive 'gotoAndStop' command

I’m working on this simple arcade game with powerups. When a powerup is hit, it does something to the player/enemy controlled mc. Among other things it should set the player/enemy mc to a different frame to change its shape. But for some reason the gotoAndStop call doesn’t respond inside the function.

It does work in the main code, where I use it to stop on the first frame when the swf starts.
I can also give another command to the mc in the function, which works properly. I’ve tested:

caller.y += 10; 

Below is the start of the function I wrote. It continues and closes properly. No compile errors are found. ‘caller’ refers to the player/enemy mc’s, whichever owns the hit. ‘target’ refers to the powerup hit. Powerup is a class (extended from Sprite), which has the int property ‘power’, referring to what it will do when hit.

function applyPower(caller:MovieClip, target:Powerup)
    trace(caller.name+", "+target.power);
        case 0://long paddle
        case 1://narrow paddle
        case 2://split paddle